Make-up and break-out mechanism for drill pipe joints



July 3, 1962 R. N. KNIGHTS 3,041,901

MAKE-UP AND BREAK-OUT MECHANISM FOR DRILL PIPE JOINTS Filed May 16, 19603 Sheets-Sheet 1 INVENTOR 'ficf/Atr N- Kmc/I s BY ATTORNEYS y 1962 R. N.KNIGHTS 3,041,901

MAKE-UP AND BREAK-OUT MECHANISM FOR DRILL PIPE JOINTS Filed May 16, 19603 Sheets-Sheet 2 lNvENToR fiat/Ar H. Kulqyfs BYW/ M ATTolNEY:

y 1962 R. N. KNIGHTS 3,041,901

MAKE-UP AND BREAK-OUT MECHANISM FOR DRILL PIPE JOINTS Filed May 16, 19605 Sheets$heet 3 INVENTQR l. KMIGHTS ATTnQNEYS atent @fiiice 3,941,991Patented July 3, 1962 3,041 901 MAKE-U? AND BREAK-bill MECHANISM FORBREE, PlilE .IQENTS Richard N. Knights, Hucclecote, England, assignor toDowty Rotol Limited, Chelt'enharn, England, a British company Filed May16, 1960, Ser. No. 29,274 Claims priority, application Great Britain May20, 1959 6 Claims. (El. 81-53) The present invention relates to earthboring equipment and more particularly to a make-up and break-out unitof the kind employed in earth boring equipment, and herein-afterdescribed, for the purposes of applying the final tightening force toscrewed-up joints between drill pipes when making up a drill pipe stringand performing the initial loosening of screwed-up pipe joints whendismantling a drill pipe string.

In U.S. patent application No. 33,158, filed June 1, 1960 there isdescribed equipments for mechanically handling strings of drill pipewhen withdrawing the string from a bore hole and automaticallydismantling from the string the individual pipes as they emerge from thehole. The equipments are reversible and maybe used to assemble pipesinto a string as the string is run back into the bore hole. Theequipment required for dismantling a string or adding single pipes to astring which is being built up includes mechanism for unscrewing andscrewing up the pipe joints under relatively light load, usually calledthe spin-off mechanism. The pipe joints are, however, finally tightenedby the makeup and break-out mechanism which is also used, of course tobreak the joints, that is to say unscrew them to the point where thespin-off mechanism can complete the unscrewing.

The actual drilling process has the effect of tightening the pipe jointsstill further and it, therefore, follows that a somewhat greater forceis required to unscrew the joints than was used when screwing them up.

In the handling of drill pipes in conventional, what may be termedmanual, rigs jaws are provided which may be brought into action by powermeans to perform these unscrewing and screwing up actions as may berequired. In general they are arranged so that they may be engaged uponthe pipe from the side, that is to say, they can open to admit the pipeand are then closed around the pipe to grip the same before they areoperated to tighten or loosen the joint. In the case of an automatic rigand provided it is of a kind in which the lifts which support the pipestring do not pass one another, the break-out mechanism can permanentlysurround the pipe string and indeed it is attractive to do this in orderto save time. In an automatic rig every pipe joint is operated upon andpipes are removed singly instead of in threes as is more customary inmanual rigs, so that it is important not to lose time bringing themechanism into engagement with the pipe and removing it at each joint.Instead the pipe merely passes through the break-out mechanism.

The present invention relates to a break-out or makeup jaw assemblyparticularly siutable for use in an automatic rig, in that it may takethe form of a compact unit which may permanently surround the pipe.

One form of make-up and break-out unit for the tool joints of a drillstring is illustrated in the accompanying drawings, in which:

FIGURE 1 is a perspective view of the unit operating on a tool jointbroken away in part to show interior details;

FiGURE 2 is a perspective view of the clamping and torque applyingcomponents of the unit operating on a tool joint, shown axiallyseparated for clarity, but with supporting cage elements omitted; and

FIGURE 3 is a plan view from below of the unit with the lower plate ofthe supporting cage removed.

The make-up and break-out unit is mounted in a skeleton framework orcage indicated generally at 5 and comprising a top plate 6 and a bottomplate 7 spaced apart and connected by three pillars 8. The bottom platehas three apertured lugs 9 by means of which the unit may be attached tothe vertical lift platform of an automatic drilling rig.

Mounted within the cage are two jaw assemblies indicated generally at 11in FIGURE 1. Both devices are similar and one is inverted in respect tothe other, while a hydraulic actuator 12 is interposed between them toprovide the torque for making or breaking the tool joint.

One such jaw assembly will be described. Essentially the devicecomprises a large jaw 13 having an inner curved surface 14 carrying twopipe-gripping pads 15 and a small jaw 16 pivoted to the large jaw 13 ona pin 17, this small jaw 16 having an inner curved surface 18 providedwith a single gripping pad 15. The three gripping pads are disposed inthe operative position of the jaws to lie substantially apart around thetool joint with which they engage. The outer ends of the jaws 13 and 16are interconnected by a load amplifying linkage which comprises a lever19 mounted on a fulcrum pin 21 at the free end of the jaw 13, the lever19 having its shorter lever arm 22 pivotally connected by a link 23 tothe small jaw 16, and its longer lever arm 24 pivotally connected to thepiston rod 25 of a hydraulic actuator. The actuator cylinder 26 ispivotally connected at 27 to an intermediate position on the large jaw13.

This large jaw 13 has a forked lug 28 which is offset to one side of thecentral plane of the jaw 13 to provide a connection for a make-up andbreak-out actuator 12 by means of a pivot pin 29 extending across theforked lug 28. Since the other jaw assembly is inverted with respect tothe one described, it will have a forked lug 28 likewise offset to oneside of the central plane of the jaw 13, and the extent to which bothsuch forked lugs are offset is arranged to bring them into the sametransverse plane so that the make-up and break-out actuator 12 operateshorizontally between them.

The large jaw of the lower pair is fixedly although resiliently locatedin the bottom plate 7 by a hinge pin 32, see FIGURE 2, forming anextension of the pin 17, which engages a soft rubber bushing therein(but not shown) to provide adequate play for accommodation movementbetween the pair of jaws and the pipe joint without straining.

The large jaw 13 of the upper pair has a pin 33, seen only in FIGURE 2,corresponding to the hinge pin 32 of the lower pair, which is locatedwithin an arcuate slot 34, FIGURE 3, in the top plate 6. The plates 6and 7 are omitted in FIGURE 2. The pin 33 in the upper jaw 13 is not tobe confused with the hinge pin 17 with which it is substantiallyco-axial in the relative positions of the two pairs of jaws shown inFIGURE 3. The slot 34 permits the required degree of angular movementduring make-up or break-out of the upper pair of jaws with respect tothe lower pair, which latter pair is stationary with respect to thehousing. The angle of movement provided by the actuator 12 and allowedfor by movement of the pin 33 in the slot 34 is sufficient both totighten up the screw joint between two pipes, and when working in theopposite direction to break-out a fully tightened joint so that theupper pipe can be removed by spinning off under a light torsional load.

The make-up and break-out actuator 12 is extended to break out a tooljoint, and it will be observed that the smaller jaw 16 will trail duringthe break-out action. The larger area of the actuator 12 is subject tofluid pressure during break-out and the grip on the tool joint is, tosome extent, augmented by the trailing shoe effect of the small jaw 16.

The jaws 13 and 16 are adapted to take interchangeable die holdershaving gripping pads 15 for engaging the tool joint. One set of dieholders 35 capable of operating with the smallest diameter of tool jointis shown in chain dot line in FIGURE 3, while the pads 15 shown in fullline can be fitted to operate on the largest size of tool joint.Clearly, the torque requirement for making and breaking joints in thetwo sizes will be widely different and it will, therefore, be convenientto vary the working pressure available at the actuator 12 accordingly.

It is to be observed that in the above-mentioned description the make-upand break-out actuator 12 operates directly between the two jawassemblies 11 which grip the respective sides of the tool joint so thatthe reaction load is taken directly one on the other and not through thelift platform, or the like as in previously known arrangements.

I claim as my invention:

1. A break-out mechanism of the kind referred to comprising an upperpipe gripping jaw assembly and a lower pipe gripping jaw assembly,mounting means interconnecting said assemblies to provide for relativeturning movement of one assembly with respect to the other substantiallyabout the pipe axis, a lug formed on the upper jaw assembly in aposition displaced towards the lower jaw assembly, a lug formed on thelower tong assembly in a position offset towards the upper jaw assembly,both said lugs being transversely separated in a common plane to whichthe pipe is perpendicular, and a hydraulic actuator pivotally interposedbetween said lugs to effect relative turning movement of the jawassemblies.

2. A break-out mechanism according to claim 1, wherein the upper andlower jaw assemblies are similarly constructed and one of saidassemblies is inverted with respect to the other.

3. A break-out mechanism according to claim 1, wherein the mountingmeans comprises a cage surrounding the pipe axis, a first, substantiallyfixed, location in the cage for one jaw assembly, and a second locationin the housing for the other jaw assembly, said second locationproviding for turning movement of said other jaw assembly substantiallyabout the pipe axis,

4. A break-out mechanism according to claim 1, wherein each jaw assemblycomprises two jaws pivoted together for opening and closing movement ina plane to which the pipe axis is perpendicular, a load amplifyinglinkage, including a lever, interconnecting the ends of the jaws remotefrom their pivotal connection, and a hydraulic actuator interposedbetween one jaw and the lever, whereby said load amplifying linkage isoperative to effect a smaller movement of the end of the other jaw towhich it is attached than the corresponding stroke of the hydraulicactuator.

5. A break-out mechanism of the kind referred to comprising a supportingcage including an upper and a spaced lower plate centrally apertured topass a pipe string, an upper pipe gripping jaw assembly and a lower pipegripping jaw assembly, locating means interengageable between each jawassembly and the corresponding plate of the cage, at least one of saidlocating means being arranged :for limited rotational movement of itsjaw assembly about the pipe axis, each jaw assembly including a pair ofjaws pivotally interconnected and means to constrict them relativelyinto gripping engagement with the pipe, and means reacting from one jawassembly directly upon the other to urge the two jaw assemblies in oneor the opposite rotational sense, to make-up or to break-out a screwjoint intermediate pipes gripped by the respective jaw assemblies.

6. A break-out mechanism as in claim 5, wherein the locating means ofone jaw assembly includes a hinge pin constituting the pivotalinterconnection between said jaw assembly and its plate, and projectingtowards said plate, and an arcuate slot in the plate centered about thepipe axis, wherein the projecting hinge pin is received.

References Cited in the file of this patent UNITED STATES PATENTS2,544,639 Calhoun Mar. 13, 1951 2,566,561 Edelberg Sept. 4, 19512,639,894 Smith May 26, 1953 2,737,839 Paget Mar. 13, 1956 2,760,392Paget Aug. 28, 1956 2,850,929 Crookston et al. Sept. 9, 1958 2,871,743Kelley Feb. 3, 1959

